C语言字符串函数大全

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C语言字符串函数大全

函数名: stpcpy

功能: 拷贝一个字符串到另一个

用法: char *stpcpy(char *destin, char *source);

程序例:

 

#include<stdio.h>

#include<string.h>

 

int main(void)

{

    char string[10];

    char *str1 = "abcdefghi";

 

    stpcpy(string, str1);

    printf("%s ", string);

    return 0;

}

 

函数名: strcat

功能: 字符串拼接函数

用法: char *strcat(char *destin, char *source);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char destination[25];

    char *blank = " ", *c = "C++", *Borland = "Borland";

 

    strcpy(destination, Borland);

    strcat(destination, blank);

    strcat(destination, c);

 

    printf("%s ", destination);

    return 0;

}

 

函数名: strchr

功能: 在一个串中查找给定字符的第一个匹配之处

用法: char *strchr(char *str, char c);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char string[15];

    char *ptr, c = ‘r‘;

 

    strcpy(string, "This is a string");

    ptr = strchr(string, c);

    if (ptr)

    printf("The character %c is at position: %d ", c, ptr-string);

    else

    printf("The character was not found ");

    return 0;

}

 

函数名: strcmp

功能: 串比较

用法: int strcmp(char *str1, char *str2);

看Asic码，str1>str2，返回值 > 0；两串相等，返回0

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char *buf1 = "aaa", *buf2 = "bbb", *buf3 = "ccc";

    int ptr;

 

    ptr = strcmp(buf2, buf1);

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 1 ");

    else

    printf("buffer 2 is less than buffer 1 ");

 

    ptr = strcmp(buf2, buf3);

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 3 ");

    else

    printf("buffer 2 is less than buffer 3 ");

 

    return 0;

}

 

函数名: strncmpi

功能: 将一个串中的一部分与另一个串比较, 不管大小写

用法: int strncmpi(char *str1, char *str2, unsigned maxlen);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char *buf1 = "BBB", *buf2 = "bbb";

    int ptr;

 

    ptr = strcmpi(buf2, buf1);

 

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 1 ");

 

    if (ptr < 0)

    printf("buffer 2 is less than buffer 1 ");

 

    if (ptr == 0)

    printf("buffer 2 equals buffer 1 ");

 

    return 0;

}

 

函数名: strcpy

功能: 串拷贝

用法: char *strcpy(char *str1, char *str2);

程序例:

 

#include<stdio.h>

#include<string.h>

 

int main(void)

{

    char string[10];

    char *str1 = "abcdefghi";

 

    strcpy(string, str1);

    printf("%s ", string);

    return 0;

}

 

函数名: strcspn

功能: 在串中查找第一个给定字符集内容的段

用法: int strcspn(char *str1, char *str2);

程序例:

 

#include<stdio.h>

#include<string.h>

#include<alloc.h>

 

int main(void)

{

    char *string1 = "1234567890";

    char *string2 = "747DC8";

    int length;

 

    length = strcspn(string1, string2);

    printf("Character where strings intersect is at position %d ", length);

 

    return 0;

}

 

函数名: strdup

功能: 将串拷贝到新建的位置处

用法: char *strdup(char *str);

程序例:

 

#include<stdio.h>

#include<string.h>

#include<alloc.h>

 

int main(void)

{

    char *dup_str, *string = "abcde";

 

    dup_str = strdup(string);

    printf("%s ", dup_str);

    free(dup_str);

 

    return 0;

}

 

函数名: stricmp

功能: 以大小写不敏感方式比较两个串

用法: int stricmp(char *str1, char *str2);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char *buf1 = "BBB", *buf2 = "bbb";

    int ptr;

 

    ptr = stricmp(buf2, buf1);

 

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 1 ");

 

    if (ptr < 0)

    printf("buffer 2 is less than buffer 1 ");

 

    if (ptr == 0)

    printf("buffer 2 equals buffer 1 ");

 

    return 0;

}

 

函数名: strerror

功能: 返回指向错误信息字符串的指针

用法: char *strerror(int errnum);

程序例:

 

#include<stdio.h>

#include<errno.h>

 

int main(void)

{

    char *buffer;

    buffer = strerror(errno);

    printf("Error: %s ", buffer);

    return 0;

}

 

函数名: strcmpi

功能: 将一个串与另一个比较, 不管大小写

用法: int strcmpi(char *str1, char *str2);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char *buf1 = "BBB", *buf2 = "bbb";

    int ptr;

 

    ptr = strcmpi(buf2, buf1);

 

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 1 ");

 

    if (ptr < 0)

    printf("buffer 2 is less than buffer 1 ");

 

    if (ptr == 0)

    printf("buffer 2 equals buffer 1 ");

 

    return 0;

}

 

函数名: strncmp

功能: 串比较

用法: int strncmp(char *str1, char *str2, int maxlen);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

 

{

    char *buf1 = "aaabbb", *buf2 = "bbbccc", *buf3 = "ccc";

    int ptr;

 

    ptr = strncmp(buf2,buf1,3);

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 1 ");

    else

    printf("buffer 2 is less than buffer 1 ");

 

    ptr = strncmp(buf2,buf3,3);

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 3 ");

    else

    printf("buffer 2 is less than buffer 3 ");

 

    return(0);

}

 

函数名: strncmpi

功能: 把串中的一部分与另一串中的一部分比较, 不管大小写

用法: int strncmpi(char *str1, char *str2);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char *buf1 = "BBBccc", *buf2 = "bbbccc";

    int ptr;

 

    ptr = strncmpi(buf2,buf1,3);

 

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 1 ");

 

    if (ptr < 0)

    printf("buffer 2 is less than buffer 1 ");

 

    if (ptr == 0)

    printf("buffer 2 equals buffer 1 ");

 

    return 0;

}

 

函数名: strncpy

功能: 串拷贝

用法: char *strncpy(char *destin, char *source, int maxlen);

程序例:

 

#include<stdio.h>

#include<string.h>

 

int main(void)

{

    char string[10];

    char *str1 = "abcdefghi";

 

    strncpy(string, str1, 3);

    string[3] = ‘‘;

    printf("%s ", string);

    return 0;

}

 

函数名: strnicmp

功能: 不注重大小写地比较两个串

用法: int strnicmp(char *str1, char *str2, unsigned maxlen);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char *buf1 = "BBBccc", *buf2 = "bbbccc";

    int ptr;

 

    ptr = strnicmp(buf2, buf1, 3);

 

    if (ptr > 0)

    printf("buffer 2 is greater than buffer 1 ");

 

    if (ptr < 0)

    printf("buffer 2 is less than buffer 1 ");

 

    if (ptr == 0)

    printf("buffer 2 equals buffer 1 ");

 

    return 0;

}

 

函数名: strnset

功能: 将一个串中的所有字符都设为指定字符

用法: char *strnset(char *str, char ch, unsigned n);

程序例:

 

#include<stdio.h>

#include<string.h>

 

int main(void)

{

    char *string = "abcdefghijklmnopqrstuvwxyz";

    char letter = ‘x‘;

 

    printf("string before strnset: %s ", string);

    strnset(string, letter, 13);

    printf("string after  strnset: %s ", string);

 

    return 0;

}

 

函数名: strpbrk

功能: 在串中查找给定字符集中的字符

用法: char *strpbrk(char *str1, char *str2);

程序例:

 

#include<stdio.h>

#include<string.h>

 

int main(void)

{

    char *string1 = "abcdefghijklmnopqrstuvwxyz";

    char *string2 = "onm";

    char *ptr;

 

    ptr = strpbrk(string1, string2);

 

    if (ptr)

    printf("strpbrk found first character: %c ", *ptr);

    else

    printf("strpbrk didn‘t find character in set ");

 

    return 0;

}

 

函数名: strrchr

功能: 在串中查找指定字符的最后一个出现

用法: char *strrchr(char *str, char c);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char string[15];

    char *ptr, c = ‘r‘;

 

    strcpy(string, "This is a string");

    ptr = strrchr(string, c);

    if (ptr)

    printf("The character %c is at position: %d ", c, ptr-string);

    else

    printf("The character was not found ");

    return 0;

}

 

函数名: strrev

功能: 串倒转

用法: char *strrev(char *str);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char *forward = "string";

 

    printf("Before strrev(): %s ", forward);

    strrev(forward);

    printf("After strrev():  %s ", forward);

    return 0;

}

 

函数名: strset

功能: 将一个串中的所有字符都设为指定字符

用法: char *strset(char *str, char c);

程序例:

 

#include<stdio.h>

#include<string.h>

 

int main(void)

{

    char string[10] = "123456789";

    char symbol = ‘c‘;

 

    printf("Before strset(): %s ", string);

    strset(string, symbol);

    printf("After strset():  %s ", string);

    return 0;

}

 

函数名: strspn

功能: 在串中查找指定字符集的子集的第一次出现

用法: int strspn(char *str1, char *str2);

程序例:

 

#include<stdio.h>

#include<string.h>

#include<alloc.h>

 

int main(void)

{

    char *string1 = "1234567890";

    char *string2 = "123DC8";

    int length;

 

    length = strspn(string1, string2);

    printf("Character where strings differ is at position %d ", length);

    return 0;

}

 

函数名: strstr

功能: 在串中查找指定字符串的第一次出现

用法: char *strstr(char *str1, char *str2);

程序例:

 

#include<stdio.h>

#include<string.h>

 

int main(void)

{

    char *str1 = "Borland International", *str2 = "nation", *ptr;

 

    ptr = strstr(str1, str2);

    printf("The substring is: %s ", ptr);

    return 0;

}

 

函数名: strtod

功能: 将字符串转换为double型值

用法: double strtod(char *str, char **endptr);

程序例:

 

#include<stdio.h>

#include<stdlib.h>

 

int main(void)

{

    char input[80], *endptr;

    double value;

 

    printf("Enter a floating point number:");

    gets(input);

    value = strtod(input, &endptr);

    printf("The string is %s the number is %lf ", input, value);

    return 0;

}

 

函数名: strtok

功能: 查找由在第二个串中指定的分界符分隔开的单词

用法: char *strtok(char *str1, char *str2);

程序例:

 

#include<string.h>

#include<stdio.h>

 

int main(void)

{

    char input[16] = "abc,d";

    char *p;

 

    /* strtok places a NULL terminator

     in front of the token, if found */

    p = strtok(input, ",");

    if (p) printf("%s ", p);

 

    /* A second call to strtok using a NULL

     as the first parameter returns a pointer

     to the character following the token  */

    p = strtok(NULL, ",");

    if (p) printf("%s ", p);

    return 0;

}

 

函数名: strtol

功能: 将串转换为长整数

用法: long strtol(char *str, char **endptr, int base);

程序例:

 

#include<stdlib.h>

#include<stdio.h>

 

int main(void)

{

    char *string = "87654321", *endptr;

    long lnumber;

 

    /* strtol converts string to long integer  */

    lnumber = strtol(string, &endptr, 10);

    printf("string = %s  long = %ld ", string, lnumber);

 

    return 0;

}

 

函数名: strupr

功能: 将串中的小写字母转换为大写字母

用法: char *strupr(char *str);

程序例:

 

#include<stdio.h>

#include<string.h>

 

int main(void)

{

    char *string = "abcdefghijklmnopqrstuvwxyz", *ptr;

 

    /* converts string to upper case characters */

    ptr = strupr(string);

    printf("%s ", ptr);

    return 0;

}

 

函数名: swab

功能: 交换字节

用法: void swab (char *from, char *to, int nbytes);

程序例:

 

#include<stdlib.h>

#include<stdio.h>

#include<string.h>

 

char source[15] = "rFna koBlrna d";

char target[15];

 

int main(void)

{

    swab(source, target, strlen(source));

    printf("This is target: %s ", target);

    return 0;

}